Method and magnetic resonance system for functional MR imaging of a predetermined volume segment of the brain of a living examination subject

Patent metadata

Field	Value
Publication number	US-9829553-B2
Application number	US-201313857311-A
Country	US
Kind code	B2
Filing date	Apr 5, 2013
Priority date	Apr 5, 2012
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

In a method and a magnetic resonance (MR) system for functional MR imaging of a predetermined volume segment of THE brain of a living examination subject, an RF excitation pulse is radiated into the subject and at least one magnetic field gradient is activated, and MR data of the predetermined volume segment is acquired beginning at a predetermined echo time after the RF excitation pulse. The echo time is in a time period of 10 μs to 1000 μs.

First claim

We claim as our invention:

1. A method of acquiring functional magnetic resonance (MR) data from a predetermined volume segment in the brain of an examination subject, comprising:
from a control computer, operating an MR data acquisition unit, comprising an RF radiator and a gradient system, in order to execute a functional MR data acquisition sequence;
from said control computer, in said functional MR data acquisition sequence, activating at least one pre-pulse selected from the group consisting of a T1-selected pre-pulse and a T2-selected pre-pulse that induce relaxation of nuclear spins in a predetermined volume segment of an examination subject, said relaxation having a relaxation duration, and during said relaxation duration, radiating an RF excitation pulse from said RF radiator that excites said nuclear spins in said predetermined volume segment of the examination subject, and operating said gradient system in order to activate at least one magnetic field gradient and acquiring functional MR data produced by excitation of the nuclear spins in said predetermined volume segment, during each of a plurality of predetermined echo times that occur after said RF excitation pulse and during said relaxation duration; and
from said control unit, operating said MR data acquisition unit in order to cause each of said plurality of predetermined echo times that occur after said RF excitation pulse to be in a time period in a microsecond range between 10 μs and 1,000 μs.

2. A method as claimed in claim 1 wherein said plurality of predetermined echo times is 2 to 500 echo times.

3. A method as claimed in claim 1 comprising, from said control unit, operating said gradient coil system in order to ramp up multiple magnetic field gradients for spatial coding of said functional MR data, simultaneously with beginning acquisition of said functional MR data.

4. A method as claimed in claim 1 comprising, from said control unit, operating said gradient coil system in order to ramp up multiple magnetic field gradients before radiating said RF excitation pulse, in order to acquire said functional MR data.

5. A method as claimed in claim 4 comprising entering said functional MR data into an electronic memory representing k-space, at respective k-space points in k-space, by entering said functional MR data into k-space points in a middle region of k-space individually so that said functional MR data are entered into only one k-space point in said middle region of k-space per each RF excitation pulse.

6. A method as claimed in claim 1 comprising entering said functional MR data into an electronic memory representing k-space, comprising a plurality of k-space points, and dividing said k-space points in k-space into a middle region of k-space and an outer region of k-space, k-space consisting of said middle region and said outer region, and entering said functional MR data into k-space points in said middle region more often than entering said functional MR data into k-space points in said outer region.

7. A method as claimed in claim 6 comprising:
entering said functional MR data into k-space repeatedly in multiple, successive time windows respectively coinciding with said plurality of predetermined echo times;
for each time window, reconstructing multiple MR images of said predetermined volume segment of the brain of an examination subject from the functional MR data acquired in that time window;
during each time window, entering said functional MR data into k-space points in a predetermined number of lines in said middle region of k-space, said predetermined number of lines corresponding to the number of said multiple MR images reconstructed from each time window; and
during each time window, entering functional MR data into k-space points in said outer region once, and reconstructing thereafter each of said multiple MR images of said predetermined volume segment of the brain of an examination subject, using a respective time window from the functional MR data entered into the middle region and the outer region while the respective time window is occurring.

8. A magnetic resonance (MR) system comprising:
an MR data acquisition unit comprising an RF radiator and a gradient system;
a control computer configured to operate said MR data acquisition unit in order to execute a functional MR data acquisition sequence;
said control computer, in said functional MR data acquisition sequence, being configured to operate said RF radiator to activate at least one pre-pulse selected from the group consisting of a T1-selected pre-pulse and a T2-selected pre-pulse that induce relaxation of nuclear spins in a predetermined volume segment of the brain of an examination subject, said relaxation having a relaxation duration, and to radiate during said relaxation duration, an RF excitation pulse that excites said nuclear spins in said predetermined volume segment of the brain of the examination subject, and being configured to operate said gradient system in order to activate at least one magnetic field gradient and acquire functional MR data produced by excitation of the nuclear spins in said predetermined volume segment of the brain of an examination subject, during each of a plurality of predetermined echo times that occur after said RF excitation pulse and during said relaxation duration; and
said control computer being configured to operate said MR data acquisition unit in order to cause each of said plurality of predetermined echo times that occur after said RF excitation pulse to be in a time period in a microsecond range between 10 μs and 1,000 μs.

9. A method as claimed in claim 8 wherein said plurality of predetermined echo times is 2 to 500 echo times.

10. A non-transitory, computer-readable data storage medium encoded with programming instructions, said data storage medium being loaded into a computerized control system of a magnetic resonance (MR) apparatus, said MR apparatus also comprising an MR data acquisition unit comprising an RF radiator and a gradient system, and said programming instructions causing said control system to:
operate said functional MR data acquisition unit in order to execute a functional MR data acquisition sequence;
in said functional MR data acquisition sequence, operate said RF radiator in order to activate at least one pre-pulse selected from the group consisting of a T1-selected pre-pulse and a T2-selected pre-pulse that induce a relaxation of nuclear spins in a predetermined volume segment of the brain of an examination subject, said relaxation having a relaxation duration, and in order to radiate during said relaxation duration an RF excitation pulse from said RF radiator that excites said nuclear spins in said predetermined volume segment of the brain of the examination subject, and to operate said gradient system in order to activate at least one magnetic field gradient and acquire functional MR data produced by excitation of the nuclear spins in said predetermined volume segment of the brain of an examination subject, during each of a plurality of predetermined echo times that occur after said RF excitation pulse and during said relaxation duration; and
operate said MR data acquisition unit in order to cause each of said plurality of predetermined echo times that occur after said RF pulse to be in a time period in a microsecond range between 10 μs and 1,000 μs.

11. A method as claimed in claim 10 wherein said plurality of predetermined echo times is 2 to 500 echo times.

Assignees

• Grodzki David
• Heismann Bjoern
• Lenger Jeanette
• Schmidt Sebastian
• Siemens Ag

Inventors

• Grodzki David
• Heismann Bjoern
• Lenger Jeanette
• Schmidt Sebastian

Classifications

• G01R33/4816

  NMR imaging of samples with ultrashort relaxation times such as solid samples, e.g. MRI using ultrashort TE [UTE], single point imaging, constant time imaging · CPC title

• G01R33/5619

  by temporal sharing of data, e.g. keyhole, block regional interpolation scheme for k-Space [BRISK] · CPC title

• G01R33/4806 Primary

  Functional imaging of brain activation · CPC title

• G01R33/54

  Signal processing systems, e.g. using pulse sequences {; Generation or control of pulse sequences; Operator console} · CPC title